The present invention relates to air compressors.
Known air compressors include a motor and a piston assembly. The piston assembly has at least one piston reciprocated by the motor. The piston or pistons are slidably mounted in bushings or sleeves and are reciprocated in the sleeves by a cam driven by the motor. As the pistons reciprocate, air is drawn into the piston assembly, compressed, and expelled. The motor is located in a motor housing and the piston assembly is located in a piston housing. The piston housing and motor housing are secured together.
The piston housing normally includes cylindrical chambers into which the cylindrical sleeves are assembled by axial movement into the chambers. One end of the sleeve is closed with a cylinder head fastened to the piston housing to form a working chamber. Thus each sleeve is totally encircled by the housing and closed at one end.
In such known air compressors the dimensions of the sleeves and the cylindrical chambers in the piston housing must be kept within a narrow tolerance. It is undesirable to have the outside diameter of a sleeve so much smaller than the inside diameter of its associated chamber that the sleeve cocks in the chamber. In order to avoid cocking of the sleeves, accurate machining of the piston housing and the bushings has been necessary.
The construction of known air compressors requires that other components as well as the sleeves and the chambers in the piston housing be manufactured to relatively close tolerances. If the tolerances are too large, the cumulative effect or stack up of the tolerances can create an assembly problem. For example, the motor has a shaft that is normally supported by a bearing in the piston housing. The shaft is keyed to a cam which drives the pistons back and forth in the sleeves in the piston housing. The piston housing is fastened to the motor housing. If the manufacturing tolerances for each component are not small, assembly can be difficult or impossible with the result that many otherwise acceptable parts are wasted.
The process of compressing air produces much heat. Most of the heat generated by known air compressors is dissipated by conduction from the sleeves through the piston housing to the ambient air. Accordingly, any structure which solves problems relating to the manufacturing tolerances of air compressor components should not detrimentally affect heat dissipation.